Commitments and Contingencies (Schedule of Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Variable Interest Entity [Line Items]
Property, plant and equipment, net	$ 3,295	$ 3,269
Trade payables	685	673
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Property, plant and equipment, net	116	119
Trade payables	37	40
Current installments of long-term debt	7	6
Long-term debt	136	137
Total	180	183
Maximum exposure to loss	$ 282	$ 228